Stabilization of Colored and Fluorescent Zones

The colored and/or fluorescent chromatogram zones obtained on derivatization should be stable for at least 30 min to enable documentation and/or quantitative evaluation to be performed. 

With fluorescent substances, this is usually very satisfactorily achieved by the use of fluorescence intensifiers (FlTs). Vol. la of the reagent books of Jork et al. gives tables of lipophilic FITS (mainly mineral oils) and hydrophilic FlTs such as polyethylene glycols, triethylamine, triethanolamine and especially Triton X-100, including areas of use. Treatment by spraying and dipping in various solvents is recommended. In gen- 

Example of an intensification of fluorescence caffeic acid derivatives 

See Section 6.3.1, Fig. 84 various species of Echinacea derivatized by the flavone reagent according to Neu and stabilized with a 2 % ethanolic solution of Magrocol 400. 

Practical Tip for stabilizing colored zones On their way from the spray cabinet or plate heater to a documentation system, colored chromatograms should be covered with a clean glass plate to minimize reactions with oxygen. 

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